Taurine can be referred to as 2-aminoethanesulfonic acid and is one of the amino sulfonic acids found in the tissues of many animals. Taurine is an extremely useful compound because it has such pharmacological effects as detoxification effect, fatigue-relieving effect and nourishing and tonifying effect. As a result, taurine finds wide applications as an essential ingredient for human and animal nutrition.
Taurine is currently produced in an amount of over 50,000 tons per year from ethylene oxide and monoethanolamine, both of which are petroleum derived chemicals. In addition to their ever increasing cost, these two starting materials are toxic and for ethylene oxide difficult to handle. An alternate process for producing taurine from non-petroleum chemical is, therefore, desirable. Such a process would be even more valuable if taurine could be produced at a lower and more stable cost.
Ethanol is easily available at reasonable cost from natural sources by fermentation as it is produced in large quantity as a fuel additive and as an industrially important chemical. Furthermore, an industrially applicable process for the conversion of ethanol into ethionic acid is already known (U.S. Pat. No. 3,637,793, incorporated herein, by reference). This invention discloses novel methods for the conversion of ethanol-derived ethionic acid into taurine.
The disclosed process can also be applied to the production of taurine from ethionic acid prepared from other materials such as ethylene and carbyl sulfate.
It is, therefore, an object of this invention to provide a process for producing taurine from ethanol via ethanol-derived ethionic acid, which is economical and more competitive than current industrial processes using ethylene oxide and monoethanolamine as starting materials.
It is another object of the present invention to disclose a process for the conversion of ethionic acid into sodium isethionate and sodium vinyl sulfonate, key intermediates for producing taurine from ethionic acid by a combined use of calcium oxide/calcium hydroxide and sodium sulfate as alkaline media.
It is a further object of the present invention to disclose a process for the cyclic use of alkali metal ions, more specifically, sodium ion in the form of sodium sulfate, sodium isethionate, and sodium ethionate, in the production of taurine from ethionic acid via key intermediates of sodium isethionate and sodium vinyl sulfonate.